This invention relates to forming battery separator envelopes for enveloping battery plates and more particularly to securing battery separator walls together to form battery separator envelopes.
In the past it has been the practice to form battery separator envelopes by interconnecting walls of battery separator through the means of adhesives, hot melts, tape or when the battery separator material was appropriately sealable through heat seals and ultrasonic sealing. In all of these instances, using the previous practices, it was usual to either butt the edges of the battery separator together where it was to be joined or to lap them over one another. It has also been the practice in the past to directly cast battery separator tubes or to sew tubes from fabric and then impregnate the fabric.
It has surprisingly been found that through the present invention the walls may be spaced from each other and interconnected through a foam member and yet no additional space is lost within the battery without deleteriously affecting the free flow area of the battery separator available to the battery electrolyte.
One prior enveloping method used with the positive plates of lead acid industrial batteries involved placing glass mats over the faces of the battery paste and then wrapping the plate around its narrow dimension with a tape of glass sliver. Then a PVC sheet is wrapped over the tape, overlapped and sealed. The PVC sheet has perforations mechanically poked in it where the paste is and is solid at the edges of the plate to reduce moss or edge shorts. The bottom edge (open edge opposite the battery post) is then inserted into a plastic shield that fits over the rectangular bottom of the PVC wrapping.